Devices having rotary shafts extending from housings, particularly impeller pumps, are usually provided with a primary seal to maintain a sealed condition between the shaft and the housing. Such seals serve to retain pump fluids, such as lubricants, in the interior of the housing, while preventing the ingress of dirt or other contaminants from the outside of the housing. The primary seal may be provided as a single seal member, or a "tandem seal" including a pair of seal members.
When it becomes necessary to remove the primary seal, either for routine maintenance or emergency replacement, the sealed condition between the housing and the shaft is broken. This not only requires an interruption in operation of the device, but also allows interior fluids to escape, and exposes the interior of the device to contamination. It is often the case in such devices that removal of the primary seal necessitates a partial disassembly and rebuilding of some interior structure, usually bearing components, on the interior of the housing.
The time lost due to seal removal represents a significant expense during the operational life of a rotary shaft device. Therefore, it would be advantageous to provide a method and apparatus by which such lost time and its associated expenses are minimized.